Neurobiologists, a type of neuroscientist, study the biology of the nervous system to determine how it functions in order to better understand and treat neurological disorders, such as strokes, Alzheimer's disease, Parkinson's disease and schizophrenia. The neuroscience paradigm: mental disorders are linked to aberrant processes in the brain. Neurons and neurotransmitters. Each neuron has four major parts: The cell body.